The Supreme Court decision Mass. v. EPA, which compelled the agency to make a decision on the waiver, also required the agency to make an
endangerment finding as to whether greenhouse gases pose a threat to human health and if so, to issue motor vehicle regulations. On Wednesday Rep. Henry Waxman (D-Calif.)’s Oversight Committee investigation revealed that Johnson in fact attempted to issue an endangerment finding and motor vehicle regulations in December, but was evidently overruled by the White House and Department of Transportation. Johnson is still being unresponsive to Waxman’s investigation, as well as the one newly opened by Rep. Ed Markey (D-Mass.) of the Global Warming Committee.

Late Wednesday night, the EPA issued new smog regulations, lowering the public health (primary) and public welfare (secondary) standards to 75 parts per billion from 84 ppb. The Washington Post’s Juliet Eilperin revealed that the EPA scientific panel was overruled in its recommendation to establish a much lower seasonal secondary standard to protect plantlife during the growing season:

Nearly a year ago, EPA’s Clean Air Scientific Advisory Committee reiterated in writing that its members were “unanimous in recommending” that the agency set the standard no higher than 70 parts per billion (ppb) and to consider a limit as low as 60 ppb.

She goes on to note that on March 6, the Office of Management and Budget’s Susan E. Dudley sent a letter to the EPA asking them to consider the effect of a too strict regulation on “economic values and on personal comfort and well-being,”. EPA Deputy Administrator Marcus C. Peacock replied that “EPA cannot consider costs in setting a secondary standard,” with the cutting retort: “EPA is not aware of any information that ozone has beneficial effects on economic values or on personal comfort and well being.”

The president’s order prompted a scramble by administration officials to rewrite the regulations to avoid a conflict with past EPA statements on the harm caused by ozone. Solicitor General Paul D. Clement warned administration officials late Tuesday night that the rules contradicted the EPA’s past submissions to the Supreme Court, according to sources familiar with the conversation. As a consequence, administration lawyers hustled to craft new legal justifications for the weakened standard.